Chemistry:Meta-Diethynylbenzene dianion

Meta-Diethynylbenzene dianion

Meta-diethynylbenzene dianion
The compound C 6H 4(C 3HO 2) 2 used for the synthesis of Meta-diethynylbenzene dianion
Names
IUPAC name Meta-diethynylbenzene dianion
Properties
Chemical formula	C6H4C2−4
Hazards
Main hazards	Extremely corrosive
Related compounds
Related bases	Ortho-diethynylbenzene dianion Para-diethynylbenzene dianion Lithium monoxide anion
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Tracking categories (test):

• SizeSet

The meta-diethynylbenzene dianion is a structural isomer of the ortho-diethynylbenzene dianion. The meta-diethynylbenzene dianion is not as strong as ortho-diethynylbenzene dianion, but it is still the second-strongest superbase. Like the ortho-diethynylbenzene dianion, the meta-diethynylbenzene dianion exists in the gas state, contrary to the other bases and superbases which exist in the solution state. In the meta-diethynylbenzene dianion, the two negatively charged ethynyl (−C₂H−2) groups are bonded to the first and third carbon atoms of the benzene ring. But in the ortho-diethynylbenzene dianion, the ethynyl groups are bonded to the first and second carbon atoms of the benzene ring. Like Ortho-diethynylbenzene dianion, Meta-diethynylbenzene dianion has no known use.

Synthesis

Step 1

A sample of meta-C₆H₄(C₃HO₂)₂ is taken.

Step 2

In this next step, the parent compound is subjected through electrospray ionization (ESI) and consequently, loses two Hydrogen atoms and therefore, acquires a charge of −2. The new compound's chemical formula is [C₆H₄(C₃O₂)₂]²⁻

Step 3

The ionized parent compound [C₆H₄(C₃O₂)₂]²⁻ is subjected to collision-induced dissociation (CID), because of which, one of the carboxylate anion loses a Carbon dioxide molecule to become [C₆H₄(C₅O₂)]²⁻.

Step 4

The meta-[C₆H₄(C₃O₂)₂]²⁻ compound is again subjected to collision-induced dissociation, because of which, the other carboxylate anion loses the other Carbon dioxide molecule and becomes meta-[C₆H₄(C₅O₂)]²⁻

Step 5

Therefore, the meta-diethynylbenzene dianion [C₆H₄(C₂)₂]²⁻ is formed, having lost, in total, two hydrogen atoms and two molecules of carbon dioxide.

The same process can generate either ortho-diethynylbenzene dianion and Meta-diethynylbenzene dianion depending on which isomer of the original compound is used.

Summary

[math]\ce{ \overset{}{C6H4(C3HO2)2 ->[\ce{ESI}][] [C6H4(C3O2)2]^{2-} ->[\ce{CID}][] [C6H4(C5O2)]^{2-} ->[\ce{CID}][] [C6H4(C2)2]^{2-}} }[/math]

• Metadiethynylbenzene dianion.png

  The compound after the first stage of collision-induced dissociation having lost a carbon dioxide molecule and retaining the negative charge.

• Meta-diethynylbenzene.png

  meta-[C
  6H
  4(C
  5O
  2)]²⁻ is subjected to collision-induced dissociation for the second time losing another Carbon dioxide molecule but retaining the negative charge. Thus, the compound, Meta-diethynylbenzene dianion is formed.

See also

• Lithium monoxide anion
• Superbases
• Collision-induced dissociation
• Electrospray ionization

List of the other isomers

• Ortho-diethynylbenzene dianion
• Para-diethynylbenzene dianion

References

Poad, Berwyck L. J.; Reed, Nicholas D.; Hansen, Christopher S.; Trevitt, Adam J.; Blanksby, Stephen J.; Mackay, Emily G.; Sherburn, Michael S.; Chan, Bun et al. (12 January 2018). "Preparation of an ion with the highest calculated proton affinity: ortho -diethynylbenzene dianion". Chemical Science 7 (9). doi:10.1039/C6SC01726F. http://pubs.rsc.org/en/content/articlehtml/2016/sc/c6sc01726f. Retrieved 12 January 2018.